The present invention relates to improved configuration of fiber feeding roller of a conventional open-end spinning apparatus.
In the conventional open-end spinning apparatus, the feeding roller disposed at the inlet for fibers in the spinning body is adapted to operate in conjunction with a pressing member as a mechanism for supplying a bundle of fibers to the combing section from which such fibers are fed further to the stripping or doffing section while being moved through the fiber carrying passage formed by and between the spinning body and the combing roller disposed therein and, simultaneously, being separated into individual fibers under the influence of combing action of said combing roller. The fibers thus separated are entrained by air stream discharged from the air outlet and then introduced into the spinning rotor, whereby said open-end fibers are spinned and twisted into a continuous length of yarn.
For supplying a bundle of fibers to the combing roller, there have been heretofore mainly two types in configuration of fiber feeding rollers both of which are so arranged as to coact with a presser for said fiber feeding purpose: One configuration of feeding roller, probably named as the grooved type, has had a number of grooves formed on the outer circumferential surface of the feeding roller body and extending either in direction straight with and parallel to the axis of said feeding roller body or in any oblique or spiral direction on said circumferential surface, the projections formed thereby between such grooves on said circumferential surface being capable of serving in conjunction with the presser to provide nip for the bundle of fibers to be supplied to the combing roller; while the other configuration of fiber feeding roller, may be referred to as the knurled type, is provided on its entire outer circumferential surface thereof with a number of knurls, e.g. in the form of pyramidal knurled projections, which act in association with the presser to nip the fibers by impaling action of those knurls for the purpose of feeding fibers to the combing roller.
However, the former grooved type fiber feeding roller, which has no knurled surface similar to that formed on the latter type, can nip the fibers more uniformly but will allow higher rate of slippage of fibers on feeding roller than the knurled type fiber feeding roller, and the difference in the rate of slippage of fibers between these two types will become more remarkable with an increase of weight of the sliver per unit length to be supplied, or with a decrease of count number of the yarn to be spinned.
On the other hand, the knurled type fiber feeding roller having no straight or spiral projections similar to those on the former grooved type can prevent fibers from slipping on feeding roller, but its knurled surface will pose a problem of irregular nipping of fibers due to their impaling action, thus becoming inferior to the grooved type in terms of U% (or variation of yarn in spinned thickness) and IPI value (or variation in yarn thickness with reference to a standard thickness) of the spinned yarn, i.e. it becoming more difficult to spin yarn successfully with a decrease of the sliver weight per unit length to be supplied, or with an increase of count number of the yarn to be spinned. In this way, these two forms of fiber feeding rollers have had complementary advantages, but also disadvantages in the same way.
Therefore, the grooved type fiber feeding roller have been used mainly for spinning fibers into a thinner yarn with relatively small weight per unit length, while the other knurled type utilized for spinning a thicker yarn having relatively large weight per unit length, thus their practical applications being limited to a narrow range of count numbers of yarn and a single feeding roller being unable to cover or handle a wide range of count numbers of yarn such as from N.sub.e 3 to N.sub.e 45.